This invention relates to a touch-operation switch, which switches by only a slight touching to a touching elecrode by a human body.
Hitherto, various kinds of touch-operation switches have been proposed and used. Such touch-operation switches are practically and widely used in electric appliances or electric machines, for instance, in electric fans or electric centrifugal dehydrators, in order to stop their operation for securing safety against inadvertent touches by a human body.
Conventionally, such touch-operation switches have been constituted in a manner that the switch detects the proximity or a touch of a human body by means of capacity change due to electrostatic induction, or that the switch detects a change of a weak electromagnetic field due to human proximity or a touch. Such conventional touch-operation switches pick up input signals of very small level, and therefore are liable to false operations due to noise. In order to eliminate such false operation, conventional touch-operation switch necessitates a complicated noise-resistant detection circuit.